Development of a lightweight authentication and dynamic key distribution protocol for mesh wireless sensor networks

Abstract

Wireless sensor networks (WSNs) with mesh topology are widely used in IoT, industrial monito-ring and smart-building applications, where battery-powered nodes must communicate securely over multi-hop paths. Conventional protocols such as TLS 1.3 with RSA-2048 impose authentication costs of about 14.3 mJ and 285 ms per handshake on an ARM Cortex-M4, which significantly shortens node lifetime, while DTLS with ECC still depends on PKI infrastructure that limits scalability.
This paper proposes a lightweight authentication and dynamic key distribution protocol for mesh WSNs. The protocol has a three-layer security architecture: initial node registration based on PBKDF2, session key establishment via Elliptic Curve Diffie–Hellman (ECDH) on Curve25519, and periodic key renewal via HKDF, which provides forward secrecy. A mathematical model is developed that links the energy cost of cryptographic operations to security parameters, allowing the trade-off between security strength and node lifetime to be estimated analytically. The practical implementation is based on the Mosquitto MQTT broker with mosquitto-auth-plugin and a Redis/PostgreSQL backend, which provides centralized authentication and fine-grained topic-level Access Control Lists (ACL) without substantial changes to node firmware. A procedure for isolating compromised nodes is also described.
Simulation in Cooja (Contiki-NG) for a 50-node STM32L4 mesh network showed an average authentication time of 8.3 ms and an energy cost of 0.42 mJ per authentication, 34 and 6.3 times faster than TLS 1.3/RSA and DTLS 1.3/ECC respectively. Battery lifetime increased to 498 h, which corresponds to a 62% reduction in overall energy consumption compared with TLS 1.3/RSA, at a 128-bit security level. The results confirm that the proposed protocol is suitable for resource-constrained IoT and WSN deployments that require long-term autonomous operation.

Keywords: wireless sensor networks, mesh topology, MQTT, authentication, ACL, key distribution, ECDH, energy-efficient cryptography.